<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        .wrap {
            width: 300px;
            margin: 100px auto 0;
        }

        table {
            border-collapse: collapse;
            border-spacing: 0;
            border: 1px solid #c0c0c0;
            width: 300px;
        }

        th,
        td {
            border: 1px solid #d0d0d0;
            color: #404060;
            padding: 10px;
        }

        th {
            background-color: #09c;
            font: bold 16px "微软雅黑";
            color: #fff;
        }

        td {
            font: 14px "微软雅黑";
        }

        tbody tr {
            background-color: #f0f0f0;
        }

        tbody tr:hover {
            cursor: pointer;
            background-color: #fafafa;
        }
    </style>
</head>

<body>
    <div class="wrap">
        <table>
            <thead>
                <tr>
                    <th>
                        <input type="checkbox" id="j_cbAll" />
                    </th>
                    <th>菜名</th>
                    <th>饭店</th>
                </tr>
            </thead>
            <tbody id="j_tb">
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>红烧肉</td>
                    <td>田老师</td>
                </tr>
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>西红柿鸡蛋</td>
                    <td>田老师</td>
                </tr>
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>油炸榴莲</td>
                    <td>田老师</td>
                </tr>
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>清蒸助教</td>
                    <td>田老师</td>
                </tr>

            </tbody>
        </table>
    </div>
    <script>
        function my$(id) {
            return document.getElementById(id);
        }
        
        var tbodyCheckboxAll  = my$("j_cbAll");
        //获取tbody中所有的小复选框
        var tbodyCheckboxs = my$("j_tb").getElementsByTagName("input");

        var tbodyCheckboxSize = 0;
        for (const tbodyCheckbox of tbodyCheckboxs) {
            //注册点击事件
            tbodyCheckbox.onclick = function (){
                if (this.checked) {
                    tbodyCheckboxSize++;
                    if(tbodyCheckboxSize == tbodyCheckboxs.length){
                        tbodyCheckboxAll.checked = true;
                    }
                }else{
                    tbodyCheckboxSize--;
                    if(tbodyCheckboxSize == 0){
                        tbodyCheckboxAll.checked = false;
                    }
                }
            }
        }


        //总的是否选择框
        tbodyCheckboxAll.onclick = function () {
            if (this.checked) {
                for (const tbodyCheckbox of tbodyCheckboxs) {
                    tbodyCheckbox.checked = true;
                }
            } else {
                for (const tbodyCheckbox of tbodyCheckboxs) {
                    tbodyCheckbox.checked = false;
                }
            }
        }
    </script>
</body>

</html>